It is known to provide, for beauty salon (professional) and home use, hair-curling implements which may be electrically heated to facilitate the setting of a curl formed by engagement of a tuft of hair in the teeth or tines of an implement having a mandrel or body from which the teeth extend and about which the tuft of hair is coiled by rotation of the implement via a handle or grip fixed to one end of the mandrel or curling body. When the tuft of hair is subjected for a sufficient period of time to the heat, it tends to retain its curled position and the implement can be withdrawn from the curl, e.g. by retraction of the teeth or tines, these words being used interchangeably to refer to projections of any shape from the body which can engage the hair.
In one class of hair curlers with retractable teeth (see U.S. Pat. No. 2,803,256 and German Pat. No. 711,723) the teeth are formed on generally flat combs which extend parallel to the longitudinal axis of the implement and are received in slits or slots of a coiling body or mandrel while camming means of the inclined ramp type are provided to enable the combs to be drawn inwardly into the interior of this mandrel and hence permit the teeth to be lowered flush with or below the outer surface of the mandrel in disengaging from the teeth. The camming means is activated by a slider or pushbutton device and in the retracted positions, the combs occupy practically the entire interior of the mandrel so that the latter cannot accommodate a heating rod satisfactorily.
In another approach to the problem, illustrated for example in U.S. Pat. No. 3,148,685, combs are provided on opposite legs of a hairpin-shaped member so that they are normally biased outwardly through slots in the surface of the coiling mandrel, the shanks being depressible inwardly through appropriate windows to retract the teeth.
Here again, since the combs lie generally in radial planes and are retracted by movement in these planes, in their retracted positions they occupy a large portion of the interior of the mandrel and preclude the installation of a heating body therein. In this case, as in the case of the system mentioned previously, the heating of the curler, if desired, is very complex.
Still another hair curler is described in U.S. Pat. No. 3,275,007 in which the aforedescribed problems are eliminated by utilizing a different approach for disengaging the teeth from the hair, for shifting the teeth into a inoperative position.
In this construction, the teeth are pivotal relative to the mandrel and reach inwardly to engage an axially shiftable body so that the latter can be moved to swing the teeth from upstanding positions into positions in which the teeth hug the outer surface of the mandrel. While this arrangement can leave the central portion of the device free to accommodate a heating unit, hair may be pinched between the recumbent teeth and the outer surface of the curling mandrel.